"Red" wrote...
In context, there is a serious flaw in your "duty to retreat"
argument: A kayaker is ABSOLUTELY UNABLE to "retreat" from a powerboat! All
he can do is snip

There is another possible flaw here, in some (most? all?) states your boat
may be recognized *as* your own home when you are aboard, and some people
live aboard their boat as a primary residence. Also, even in states that
require you to "retreat", there are usually extenuating circumstanses that
may be recognized as legal allowing you to stand if you cannot, for one
reason or another, retreat without futher endangering your life.

Indeed, the laws as well as the perceptions change significantly when you
transition from kayak to sailboat or powerboat. Also, laws are in a constant
state of flux as court decisions contradict or modify current law as to the
definition of a "home" in the context of a boat or RV. While the case of a
liveaboard or a RV driver on extended vacation is more clear, a kayak (context
of OP's original question) would almost never be considered a "home," even
though it is legally recognized as a "vessel."